Lower Limb Deep Vein Diameters Beneath Medical Compression Stockings in the Standing Position.

OBJECTIVES: The mechanism by which compression therapy works is still discussed, especially at calf level. Whether lower limb deep vein diameters change under compression stockings is a matter of debate: no change versus great change. New study material helps to address this question. METHODS: This was an experimental single centre controlled study on nine selected patients with mild to moderate superficial venous disease. A total of 34 deep vein segments were examined. A new hybrid (elastic + non-elastic materials) cuff pressure device enabled the deep vein diameter changes from baseline to occlusion similar to that which could be observed under stockings. The deep vein diameters were measured through the device with the patients in a standing position and their body weight distributed equally on both legs. This was compared to a 20-35 mm Hg medical compression stocking. The diameter change when patients put their whole body weight on the tested leg was also measured. RESULTS: A pressure of 25.3 ± 6.4 mm Hg (mean, SD) was required to ovalise lower leg deep veins and a pressure of 43.1 ± 16.2 mm Hg (mean, SD) to occlude them. Both pressures were significantly different from baseline: p = .003 and p < .0001, respectively. No diameter reduction was achieved when the stockings were worn, and occlusion of deep veins occurred when the patients transferred their body weight onto the examined leg. CONCLUSION: In the standing position, deep vein diameter reduction is not caused by compression stockings but may be due to the isometric muscle contractions required to support the patient's body weight.

Prediction of the biomechanical effects of compression therapy on deep veins using finite element modelling.

Clinicians generally assume that Medical Compression Stockings (MCS) work by reducing vein luminal diameter and, in this way, help to prevent blood pooling. Conflicting results have been reported however in the case of lower leg deep veins which call into question this hypothesis. The purpose of this contribution is to study the biomechanical response of the main lower leg deep veins to elastic compression and muscle contraction with the objective of improving our current understanding of the mechanism by which MCS convey their benefits. The development of a finite-element model of a slice of the lower leg from MR images is detailed. Analysis of the finite-element model shows that the contribution of the MCS to the deep vein diameter reduction is rather small, and in fact negligible, compared to that of the contracting muscle (3 and 9% decrease in the vein cross-sectional area with a grade II compression stocking in the supine and standing positions respectively, while complete collapse was obtained at the end of muscle activation). A more accurate representation of the muscle activation is eventually proposed to study the effect of muscle contraction on a vein wall. The impact on the venous blood draining is discussed.

Local effect of compression stockings on skin microcirculatory activity through the measurement of skin effective thermal conductivity.

This paper presents a preliminary study to demonstrate the instantaneous local effect of compression stocking (Class 2) on skin microcirculatory activity. The measurement needs to be carefully performed as the sensor is placed under the garment. To assess the local effect of compression stockings, we use the ambulatory device Hematron located on the calf under the garment. Skin microcirculatory activity is assessed through the skin's effective thermal conductivity measurement. A specific housing for the sensor has been designed to avoid excessive pressure induced by the sensor when squeezed by stockings. The experiment, conducted on ten healthy subjects, comprised two stages: without and with compression stockings. Skin effective thermal conductivity was recorded at three successive positions (supine, sitting and standing). Significant improvement in skin microcirculatory activity was recorded by the Hematron device for the three positions. We have also demonstrated that Hematron sensor can be used under compression stockings.

Introducing knowledge of wearing compression stockings on the skin blood flow by using microHematron device.

The aim of this preliminary study was to review the actual state of knowledge concerning the mechanisms underlying compression medical stockings action on the skin blood flow (SBF) in capillaries. SBF was assessed by measuring the thermal conductivity of living-tissues using microHematron ambulatory device. The investigation was performed for different postures using three standard French classes (10-15 mmHg, 15-20 mmHg and 20-36 mmHg) of Medical compression stockings (MCS) on six healthy subjects without chronic venous insufficiency. The experiment was divided into four stages (supine, sitting, standing and walking) and was repeated for each class of compression stockings and without MCS. The results showed a significant improvement of SBF depending on the class of MCS used. Best results were obtained for the Class III, which exerts to the highest level of pressure exerted around the ankle. Due to the low number of subjects, which therefore reduces the statistical relevance of results, a non-significant difference in SBF due to the subject's posture was observed. Nonetheless, a positive action by all the classes of MCS on SBF was measured for the supine position. This is a very important result; with patients with chronic venous insufficiency have often some mobility reduction, MCS may enhance their microcirculation even at rest.

Comparison of low-strength compression stockings with bandages for the treatment of recalcitrant venous ulcers.

OBJECTIVE: To compare the proportion and rate of healing, pain, and quality of life of low-strength medical compression stockings (MCS) with traditional bandages applied for the treatment of recalcitrant venous leg ulcers. METHODS: A single-center, randomized, open-label study was performed with consecutive patients. Sigvaris prototype MCS providing 15 mm Hg-25 mm Hg at the ankle were compared with multi-layer short-stretch bandages. In both groups, pads were placed above incompetent perforating veins in the ulcer area. The initial static pressure between the dressing-covered ulcer and the pad was 29 mm Hg and 49 mm Hg with MCS and bandages, respectively. Dynamic pressure measurements showed no difference. Compression was maintained day and night and changed every week. The primary endpoint was healing within 90 days. Secondary endpoints were healing within 180 days, time to healing, pain (weekly Likert scales), and monthly quality of life (ChronIc Venous Insufficiency Quality of Life [CIVIQ] questionnaire). RESULTS: Of 74 patients screened, 60 fulfilled the selection criteria and 55 completed the study; 28 in the MCS and 27 in the bandage group. Ulcers were recurrent (48%), long lasting (mean, 27 months), and large (mean, 13 cm2). All but one patient had deep venous reflux and/or incompetent perforating veins in addition to trunk varices. Characteristics of patients and ulcers were evenly distributed (exception: more edema in the MCS group; P = .019). Healing within 90 days was observed in 36% with MCS and in 48% with bandages (P = .350). Healing within 180 days was documented in 50% with MCS and in 67% with bandages (P = .210). Time to healing was identical. Pain scored 44 and 46 initially (on a scale in which 100 referred to maximum and 0 to no pain) and decreased within the first week to 20 and 28 in the MCS and bandage groups, respectively (P < .001 vs .010). Quality of life showed no difference between the treatment groups. In both groups, pain at 90 days had decreased by half, independent of completion of healing. Physical, social, and psychic impairment improved significantly in patients with healed ulcers only. CONCLUSION: Our study illustrates the difficulty of bringing large and long-standing venous ulcers to heal. The effect of compression with MCS was not different from that of compression with bandages. Both treatments alleviated pain promptly. Quality of life was improved only in patients whose ulcers had healed.

Compression stockings reduce occupational leg swelling.

BACKGROUND: Evening edema of the legs is a physiologic phenomenon occurring after sitting and standing. OBJECTIVE: The objective of this study was to investigate which compression pressure is necessary to prevent leg swelling. METHODS: In 12 volunteers, the volume of both lower legs was measured in the morning and 7 h later, the difference being defined as evening edema (mL). The procedure was carried out for 4 days, in which the subjects wore below-knee stockings of different compression levels alternatively on one leg only in a random order. Compression pressure was assessed using the HATRA device. RESULTS. The average evening edema of the noncompressed legs was 62.4 mL on the left side and 94.4 mL on the right side (n.s.). Evening edema was significantly reduced to 40.3 mL by light support stockings, to -34.1 mL by compression class A, to -39.6 by compression class I, and to -59.1 mL by compression class II. Mainly stockings exerting a pressure above 10 mmHg improved subjective symptoms. CONCLUSION: Calf-length compression stockings with a pressure range between 11 and 21 mmHg are able to reduce or totally prevent evening edema and may therefore be recommended for people with a profession connected with long periods of sitting or standing.